The upcoming 4.0 reference release of Apple's iPhone OS will deliver new support for running multiple concurrent third party apps, and allow users to switch between them using a windows management mechanism similar to one made popular on the company's Mac OS X operating system.

The technology, detailed by people familiar with Apple's plans for the new firmware, will finally allow users to launch multiple apps in the background and quickly switch between them, as AppleInsider exclusively reported earlier this month. Currently, a running app must be quit when the user returns to the Home screen.

Apple initially avoided an app model supporting multiple apps running at once to help preserve battery life and simplify the user experience. Other platforms that do support the launching of multiple apps, including Android and Windows Mobile, require users to manually manage system resources and kill off performance robbing background tasks.

Today's iPhone 3.x firmware is a fully preemptive multitasking operating system, but it artificially restricts apps (other than specific ones bundled with the system by Apple) from running in the background.